Post some pictures if you can...
Well I know very little about the 10 but by the pictures I have seen you should have enough wheel base to fit a 700R4 or 4L60E transmission behind the chevy engine. Unless the 307 needs to be replaced I would go to a salvage yard and find a TBI system off a late model Chevy truck with a V8 and one of the fore mentioned transmissions, look for one with a NP205 transfer case and you won't have to worry about an adapter. Then pull the TBI, wiring harness, transmission and transfer case, bolt them behind the 307 and install the TBI now you have a fuel injected Chevy with an overdrive transmission.
Check these guys out for some tips on the TBI install... http://www.bustedjeep.com/projects/junkyardtbi.asp
Look up the casting numbers on the 307 and see if it is the truck or car version, some of the car ones are worth some money to guys restoring old Chevy's. Not to mention the truck versions have a real stout bottom end but not much power.